Assignemnt list web part giving error

I have configured the SLK on my SharePoint central admin and enabled the feature in the site collection and populated the WebPart gallery with WebPart, when I try to drag and drop the WebPart getting the following error.

"This site is not configured to use SharePoint Learning Kit. Administrators can use SharePoint Central Administration to configure SharePoint Learning Kit."

This error usually happens when you have configured SLK for a different site collection than the site containing the web part. I would start by going back to central admin and making sure you configured SLK for the right site collections. Sometimes you
can configure it for the central admin site itself, or some other site collection.